Imagers may use antennas to detect electromagnetic radiation. Imagers may be useful for many applications, including scientific equipment, surveillance equipment, targeting equipment, and military applications. One example of an imager that uses antennas to detect electromagnetic radiation is a millimeter wave imager. Millimeter wave imagers may be used, for example, as whole body imaging devices for detecting objects concealed underneath a person's clothing. Some imagers may use heterodyne sensors, however, that increase the size and weight of the imager.